A young woman presented with 5 months of progressive swelling along her right posterior mandible and associated discomfort with mastication. Her wisdom teeth had been extracted 3 years prior, and she developed dry sockets postoperatively, with food persistently becoming lodged in the right retromolar trigone area. She had not experienced fevers, neck masses, weight loss, or other head and neck symptoms. She was a university student, did not smoke, and consumed alcohol occasionally. Physical examination revealed a 1 × 1-cm soft-tissue mass along the right posterior mandibular alveolar ridge. Computerized tomography demonstrated a soft-tissue mass measuring approximately 13 × 9 mm extending into the right retromolar trigone with loss of the intervening fat and soft-tissue planes, contiguous with the right maxillary alveolus (Figure, A and B). Decreased attenuation was present along the right posterior mandibular body, likely from previous third molar wisdom tooth extraction, and appeared to be contiguous with the soft-tissue mass with slight bony remodeling. The mass was isodense with adjacent normal muscle and did not enhance with intravenous contrast. Given the slow-growing and symptomatic nature of the mass, excision was performed. The resection specimen showed a 2.0 × 1.2-cm gray-tan to pink-red, focally congested, rubbery, raised mass on gross examination. Light microscopy revealed a superficially ulcerated spindle-cell neoplasm with intersecting fascicles of uniform spindle-shaped nuclei, minimal mitotic activity, and no necrosis (Figure, C and D). Immunohistochemical staining showed lesional cells that expressed diffuse smooth muscle actin staining, and were negative for S-100 and h-caldesmon. The patient was clinically and radiologically disease-free 6 months after surgery.